The purpose of the project is to examine individual, situational, organizational, social forces, and public policy differences associated with variation in rates of homicides by police officers. The project has already examined a number of measurement issus present in currently available data sources on police homicides, and is now proceeding to the substantive analysis of those data. The analysis will first describe the nature and distribution of police homicide events in relation to the characteristics of the police and citizens involved in the situations. It will then test a variety of hypotheses about the differences in police homicide rates. Finally, it will evaluate efforts to reduce the rate of police homicides in three cities and fifteen states through changes in law and police department policy. Individual level variables to be examined include police officer's age, race, assignment, education, and father's occupation. Situational variables to be examined include nature of police intervention, nature of pre-intervention situation, victim/target's response to police intervention, and victim's armament and prior crime record. Organizational variables to be examined include administrative intensity, span of control, differentiation, self-regulation, personnel composition, and policies restricting use of deadly force. Social forces variables to be examined include social cohesion, social inequality, relational distance, occupational structure, and race and age composition.